Lindemann Audio Germany MB55 amplifier (Custom class D).

Search on line for Lindemann Audio Musicbook 55 amp review. This unit is brand new and factory sealed. 100% designed, engineered and manufactured in Germany. Punchy, well-contoured lows, most delicately sculptured highs and an extremely natural and homogeneous vocal reproduction are the strong points of this new power amplifier.

The musicbook: 55 is a class D stereo power amplifier based on a multi-patented circuit design, the UCD amplifier. Owing to a circuit layout that’s been reduced to the essentials, a discrete circuit design and careful fine-tuning the musicbook: 55 achieves a sound quality that makes a lot of big bolides look pretty much outdated. A sound, so rich in detail, natural and particularly dynamic! Just lend your ear and you’ll be surprised at how good class D can sound these days.

Summary:
Reference level class D power amplifier
Output power 2x240 W (stereo) or 1x450 W (mono bridged)
Configurable: stereo, mono bi-amping, mono bridged
Patented UCD technology
Discrete circuit design
Extremely short and logical signal path
Open, natural and dynamic sound image

In stand-by mode the yellow LED is permanently lit and will flash during operation. A high-sensitivity signal detector switches the unit automatically on and off, thereby avoiding needless energy consumption.

Mains voltage: 100–240 V, 50–60 Hz
Dimensions: 280 x 220 x 65 mm (W x D x H). Weight: 3.7 kg
Power consumption: 0.5 W standby mode, 1.0 W idle mode, 800 W max.

Protection circuits
DC at output: power supply switches off.
Excess temperature: amplifier goes into mute until the temperature has dropped by approx. 10 °C.
Output current limiter: amplifier goes into mute for ca. 0.25 seconds. Switching threshold 16 A peak. In case of continuous overdrive the amplifier will go on and off several times in a row.
Automatic turn-on
Input signal switching threshold: approx. 0.5 mV.
Idle mode: power supply active, amplifier muted. Power consumption 1.0 W.
Standby mode: only stand-by power supply active. Power consumption 0.5 W
Active mode: power supply and amplifier both active. Power consumption depending on volume level 20-50 W average, 800 W max. peak power.
Switch-on times: approx. 2 seconds from idle to active mode; approx. 8 seconds from standby to active mode.
Switch-off times: after 20 minutes the amplifier will return to idle mode, after another 20 minutes to standby mode.

Power Amplifiers
XLR inputs: analog line level inputs with 20 kOhms input impedance.
RCA inputs: analog line level inputs with 10 kOhms input impedance.
Speaker outputs: safety banana lab sockets (4mm) for connecting loudspeakers with 4–8 ohms.
Power output: 240 W into 4 ohms per channel (<1 min).
Maximum output current: 16 A peak.
Gain: 27.8 dB (24.5-times).
Frequency response: 0 Hz – 45 kHz (-3 dB).
THD & noise: <0,05% typ.

The musicbook: 55 is a class D stereo power amplifier based on a multi-patented circuit design, the UCD amplifier. Owing to a circuit layout that’s been reduced to the essentials, a discrete circuit design and careful fine-tuning, the musicbook: 55 achieves a sound quality that makes you forget about a class D amp being at work. Ultra short signal paths, finest electronic components and a well-calculated negative feedback guarantee a superb, frequency-dependent linearity of the important damping factor and distortion spectrum parameters. True to the "Power on Demand" motto this amplifier offers at the same time a dynamic, detailed and punchy sound with great high-frequency resolution! Those who love live music will quickly take this amplifier to their hearts. Small dimensions, an extremely modest power consumption and low heat up due to a high efficiency are further assets. The ideal amplifier for relaxed music enjoyment.

By means of a selector switch the musicbook: 55 is configurable for three different operating modes. In addition to a pure stereo mode, the musicbook: 55 can also be used either in mono mode as a bi-amping amplifier or balanced as a bridged power amp. With many speakers the "vertical" bi-amping produces a considerable gain in transparency and imaging quality with far less colourations. The high-mid range is relieved from the woofer "burden" and behaves like in an active loudspeaker. As distinct from traditional bi-amping, where a second stereo power amp is linked to the speakers, the configuration options of the musicbook: 55 make additional signal cables dispensable with the added benefit of a much better channel separation. The fact that one power amp handles both low and mid-high signals yields an extra plus in coherency and dynamics, since the bass power amp can draw on more than 80% of the power supply’s total output